Thermoplastic composition plasticized with monopropyl dixylyl phosphate



Patented Feb. 2, 1,954

Gizam WITH PHosPH-'Alrnf Hdrban- Irvingtoni liranky Berardiil, nglige rolira-wingsJpncationimgustf15;;195o,

swarm 179,642 7i dialing. (c1. fot-#1775) r' This invention' relates1561 phosphate estrsa'd' lts; more' particularly rhooropl. diiillphbsplatad 'to'. thermoplastic compositioscotaiiiig thesal'ne. Phosphateesters have long been sd as'plasti'- cizers for the productionofthermoplastic compositions. particularlyv vinyl: resin compositions.Tober suitable for `thispurposegrthe phosphateesters .shouldiinpar'tagoodi-iflexibility'tothe thermoplastic compositions containing-the same,fbothv at fooin;temper aturesi and ai; reduced tempera# tures:yaddition, the? plasticised: thermoplastic compositionsshould.- exhibit alow ammability, a. highresistanceto oil.` a'ndx water'V extraction andalow volatil-itsgwi-th respect to theplasticizer, and a good..stabilityY to. heat and:n light sothat said` thermoplastic compositionswill retain theirproporties duringiusef Itis ani important-- obiectcfthis; invention toprovidealnovel phosphateester which will fulfilltheiforegoing. requirements when? employedas a plasticizen inthermoplastic compositions andf which willihe simple andinexpense toyproduce' from readily@availablenew'materials:7

AT furthenpbect of thisinvention-is to providea thermoplastic.compositionplastici'zedl withr monopropyll diiiylyllphosphate.`

' Another objectl of. this inventionA is to Y providenprocess/for.the-productionofmonopropyldixylyl phqspha'ts' l Y.

Otherobj ects L this-iin-ventonwill befapparent: from the followingJdetailed. description aridI claims Accordingv to1 thepresent invention,4we have found; that.. monopropyL. diiiyll phosphate isf angexcellntfplasticizing agentifor. the production ot thermoplastic` Vcompositi ons.u particularly vinylf resin@ compositionsrThemonopropyldixy-lyl phosphate impartsgood ilexibility totherm plasticcompositions containing the same both at room temperaturesff aridrediced temperatures. Infadditionp.the=thermop1astic compositions-1plasticizediwith-fmonopropyl dixylyl phosphate 'exhibit`V a.-4 lowammahilityg. a high resistance yto? oili andweten' extrectioriaanda-flow volatility;witlfvrespecttwthe-monopropyldixylylfphosphate;andaigood-`v stability, to heat and1 lightfsof t1-1at1-'saidthermo--plastic compositions` retain their propertiesa durasf niftyriiyuroemonclacidiniihefreceoonnimmer and thereby assist in carrying thereaction to completion. The resultant mixture is neutralized by theaddition thereto of an alkaline material such as sodium carbonate, forexample, and the upper aqueous phase is separated and discarded. Thelower phase, containing the phosphate esters is washed to removeinorganic salts therefrom, which washing may, if desired,` `be carriedout on a solution of the phosphate ester in an organic solvent such asethyl ether, for example. The solvent is evaporated together with anywater and propanol and the product distilled under reduced pressure toseparate from the monopropyl dixylyl phosphate any dipropyl monoxylylphosphate and trixylyl phosphate which has formed. The monopropyldixylyl phosphate may, if desired, be treated with strong oxidizingagents, such as potassium perman'ganate in aqueous solution, followingwhich, the aqueous phase is separated rom the monopropyl dixylylphosphate and the latter is distilled at reduced pressure to remove alltraces of Water therefrom and is nally ltered.

The novel thermoplastic compositions of this invention may be preparedby incorporating from about l to 150 parts by weight of monopropyldixylyl phosphate in 100 parts by weight of an organic plastic such as,for example, a vinyl resin, including polyvinyl chlorides, vinylchloride/vinyl acetate/copolymers and polyvinyl butyrals, a cellulosederivative, such as cellulose nitrate, cellulose acetate, cellulosepropionate, cellulose butyrate, cellulose acetate propionate, celluloseacetate butyrate and ethyl cellulose, polystyrenes, polymethylmethacrylates, chlorinated rubbers, and synthetic rubbers, such as BunaN. The thermoplastic compositions may contain, in addition to themonopropyl dixylyl phosphate, other plasticizers, stabilizers, fillers,anti-blocking agents, lubricants, ultra-violet light absorbents, dyes,pigments, nacreous substances, and other eiect materials.

The following examples are given to illustrate this invention further.

Eample I To 1185 parts by weight of phosphorus oxychloride thereis added1880 parts by weight of commercial xylenol, which comprises a mixture ofisomeric xylenols, and the mixture is heated gradually over a period of6% hours to a peak temperature of 272 C. at which time the hydrogenchloride evolved is equal to 2 moles for each mole of phosphorusoxychloride employed. Any monoxylyl dichlorophosphate which has formedis stripped from the reaction mixture by heating the same to atemperature of 195 C. at a pressure of about 5 mm. of mercury absoluteleaving a residue of 2223 parts by weight containing 1724 parts byweight of dixylyl chlorophosphate or 69% of theory based lon thephosphorusl oxychloride.

To 1090 parts by weight of the stripped reaction mixture containing 845parts by weight of dixylyl chlorophosphate there is added 345 parts byweight of n-propyl alcohol and the mixture is heated to a temperature of45-75 C. for 6 hours. The reaction mixture is then neutralized by theaddition of a solution containing 164 parts by weight of sodiumcarbonate dissolved in 1500 parts by weight of water. The upper aqueousphase is siphoned oi and the lower phase, containing the phosphateesters, is dissolved in 1130 parts by weight of ethyl ether and washedwith Water to remove therefrom any inorganic salts.

The ether solvent is evaporated :and the crude product heated to 93 C.at a pressure of l mm. of mercury absolute to remove any remaining waterand n-propyl alcohol. The crude product is distilled at a pressure of 1mm. of mercury absolute and the fractions boiling between 193 and 220 C.are collected. There is obtained a yield of 707 parts by weight ofmonopropyl dixylyl phosphate or 78% of theory based on the dixylylchlorophosphate in the stripped reaction product.

The monopropyl dixylyl phosphate may, if desired, be further puried bytreating with charcoal, bleaches, diatomaceous earth, lter aids, etc.,and filtered, or it may be simply washed and distilled.

The final product is substantially free from oxidizable materialsasvshown by shaking a 20 m1. sample thereof with 20 ml. of anaqueouspotassium permanganate solution containing 0.34 gram per liter ofpotassium permanganate. At the end of 30 minutes, the aqueous phaseretains its purple color.

` Example II To 640 parts by weight of phosphorus oxychloride there isadded 6 parts by weight of aluminum chloride and 1000 parts by weight ofcommercial xylenol, and the mixture is heated gradually to 80 C., atwhich point the reaction commences. and then slowly up to C. over aperiod of 4 hours, and then up to a peak temperature of 160 C. over aperiod of 2 hours. There is obtained 1275 parts by weight of a reactionmixture containing about 60% by weight dixylyl chlorophosphate.

The reaction mixture is cooled to 50 C. and there is added thereto 318parts by weight of npropyl alcohol. The temperature of the mixture isbrought as quickly as possible to 75 C.A and held at this point for 1hour. The reaction mixture is then neutralized by the addition of anequal weight of aqueous sodium carbonate solution, containing grams ofsodium carbonate per liter of solution, which is added rapidly to the onthe crude mix charged. The monopropyl dixylyl phosphate boils at to'230C. at a pressure of 2 mm. of mercury absolute, has a density of 1.116 to1.119 at 25/25 C. and a refractive index of 1.5218 at 25 C.

Example III A thermoplastic composition is prepared by blending, on atwo roll mill at a temperature of 150 C., 100 parts by weight of acopolymer, con- `taining 95% by weight of vinyl chloride and 5% byweight of vinyl acetate, with 55 parts by weight monopropyl dixylylphosphate, 1.6 parts by weight of basic lead carbonate as a stabilizerand Y tion, are cut from the 0.050 sheet and tested for tDumbbell-shaped speciaees'giie hibit a breakingstrength of 59 pounds andan l elongation at the breaking point of 145%.

Ihe resistance of the thermoplastic composition to water extraction isdetermined by immersing a 0.10 inch film of the same in water at 25 C.At the end of 5 days the lm shows a total weight loss of 0.10% and atthe end of 10 days the ilm still shows a weight loss of only 0.10%.

The resistance of the thermoplastic composition to oil extraction isdetermined by immersing a 0.01 inch lm of the same in a mineral oil at25C. At the end of 10 days the film shows a total weight loss of 3.6%.

The volatility of the thermoplastic composition is -determined bysuspending a 3 by 8 inch specimen of 0.01 inch lm in an air ovenmaintained at 60 C. and through which air is blown at a velocity of 2 to3 cubic feet per minute. At the end of 10 days the lm shows a totalWeight loss of 1.5% and at the end of 20 days the lm shows a totalweight loss of 2.6

The heat stability of the thermoplastic composition is determined byplacing 0.75 by 0.5 inch specimens of 0.075 inch film on a sheet oftinplate which is maintained in an oven at a temperature of 150 C. Thespecimens show a noticeable discoloration after 3 hours and do not showa very bad discoloration until after hours.

The light stability of the thermoplastic composition is determined byplacing a 31/2 by 21/2 inch specimen of 0.01 inch film in a Fadeometer.At the end of 24 hours the specimen is only very slightly discolored.

Vinyl resin compositions plasticized with monopropyl dixylyl phosphateexhibit physical properties superior to those of vinyl resincompositions plasticized with other plasticizing agents commonly usedfor this purpose as shown in the following table.

Breakmstrength, elongation, Perl s. cent Physical Properties 25C 0C 3025C 0C 30 Tricresyl phosphate 43 67 82 400 125 l5 Dioctylphthalate 38 5552 485 310 210 Mono-octyl diphenyl phos- Mphate. i...1. 1. 34 51 52 480295 230 ono ropy xyy p osphale 38 57 59 410 208 145 Weight Loss, PercentByExtraetion In- By Volatilization in Circulating Air Oven at 60 C.Water Oil, Dgys Dlgys Days 10 Days 2o Days Tricresylghosphate .04 .060.6 .14 .23 Doctylp thalate .16 .20 5.8 .64 1.49 Mono-octyl diphenylphos- Mphate..-:- --l .12 .18 8.0 1.9 4.5

onopropy ixyy p osphate .10 .10 3.6 1.5 2.6

While the vinyl resin compositions plasticized 6.. with monopropylIdixylyl phosphate suffer a greater loss in elongation at reducedtemperatures than certain vinyl resin compositions plasticized withother plasticizing agents, their elongation at these reducedtemperatures is fully adequate for commercial use. lIn addition, themonopropyl dixylyl phosphate plasticized vinyl resin compositions Willretain their properties during use yowing to their improved resistanceto extraction and volatilization, whereas vinyl resin compositionsplasticized with certain other plasticizing agents will suffer aprogressive loss in properties during use as the plasticizing agents areextracted and volatilized therefrom. l f' Eample IV A 2-mi1 nlm isprepared by casting onto a smooth surface a solution containing parts byweight of cellulose acetate having an acetyl value of 54.5, calculatedas acetic acid, 30- parts by weight of monopropyl dixylyl phosphate and300 parts by weight of acetone. The lm is stripped from the castingsurface and heated to C. in an oven to eliminate all traces of acetonetherefrom. The resultant solvent-free ilm is clear and tough and doesnot support combustion. O-n chewing the film, absolutely no taste can bedetected, indicating the suitability of the monopropyl dixylyl phosphateas a plasticizer for food wrapping materials.

Example V To 100 parts by weight of finely ground cellulose propionatecontaining 0.3 free hydroxyl groups per glucoside unit, there is added30 parts by weight of monopropyl dixylyl phosphate as prepared inExample I. After stirring the mixture Well, it is molded for 15 minutesat 200 C.

to form av disc. The disc is clear and tough and non-brittle whensubjected to shock.

Example VI impact bars. The bars are clear and exhibit an impactstrength of above 8 ft. lb./in. notch at room temperatures and anexcellent impact strength at reduced temperatures.

It is to be understood that the foregoing detailed description is givenmerely by Way of illustration and that many variations may be madetherein without departing from the spirit of our invention.

Having described our invention, what We desire to secure by LettersPatent is:

1. A thermoplastic composition' comprising an organic plastic, selectedfrom the group consisting of vinyl chloride polymers, cellulose estersand cellulose ethers, plasticized with monopropyl dixylyl phosphate.

2. A thermoplastic composition comprising polyvinyl chloride plasticizedwith monopropyl dixylyl phosphate.

3. A thermoplastic composition comprising cellulose acetate plasticizedwith monopropyl dixylyl phosphate.

4. A thermoplastic composition comprising cellulose propionateplasticized with monopropyl dixylyl phosphate.

5. A thermoplastic composition comprising 7 ethyl cellulose plasticizedwith monopropyl dixylyl phosphate.

6. A thermoplastic composition comprising an organic plastic, selectedfrom the group consisting of vinyl chloride polymers, cellulose estersand cellulose ethers, plasticzed with from about 10 to 150 parts byWeight of monopropyl dixylyl phosphate for each 100 parts by weight ofthe organic plastic.

7. A thermoplastic composition comprising polyvinyl chloride plasticizedwith from about 10- to 15G parts by weight of monopropyl dixylylphosphate for each 100 parts by weight of the polyvinyl chloride.

WILLIAM B. I-IORBACK. FRANK BERARDINELLI. WALTER D. PAIST.

References Cited in the le of this patent UNITED STATES PATENTS Number

1. A THERMOPLASTIC COMPOSITION COMPRISING AN ORGANIC PLASTIC, SELECTEDFROM THE GROUP CONSISTING OF VINYL CHLORIDE POLYMERS, CELLULOSE ESTERSAND CELLULOSE ETHERS, PLASTICIZED WITH MONOPROPLY DIXYLYL PHOSPHATE.